This is a Continuation of Application No. PCT/JP01707635 filed Sep. 4. 2001. The entire disclosure of the prior application is hereby incorporated by reference herein in its entirety.
1. Field of the Invention
The present invention relates to an electric oil pump control device for a vehicle, which effects activation and suspension of an operation of a driving source, such as an engine or a motor, while the vehicle is running.
2. Description of the Related Art
Conventional control devices capable of automatic activation and automatic suspension exist or have been proposed. These control devices automatically suspend operation of an engine under predetermined suspension conditions, such as when a running vehicle stops at a crossing or the like, and thereafter automatically activates the engine under predetermined activation conditions, such as when an accelerator pedal is depressed. Such control, generally referred to as eco-run control, is valuable for saving fuel and reducing emissions.
Motor vehicles are generally equipped with various kinds of hydraulic mechanisms, including an automatic hydraulic transmission, which operate utilizing oil pressure. Commonly, working oil pressure is supplied to these hydraulic mechanisms by means of a mechanical oil pump directly connected to a crank shaft of an engine. In vehicles adapted to the above-mentioned activation and suspension control, a second pump of an electric oil pump is additionally provided and used to continue oil supply when operation of the first mechanical oil pump is suspended accompanying suspension of engine operation, so that a hydraulic mechanism such as a transmission can operate without delay. Provision of a similar second pump is useful also for a hybrid vehicle in running using a motor-generator, which runs using, while switching, an engine and a motor-generator as a driving source, and also useful for an electric vehicle which runs using a motor-generator alone because operation of the motor-generator is generally suspended while the electric vehicle halts moving.
However, long term use of just a second pump alone for running of the vehicle may cause problems including accelerated deterioration of the pump and requirement for a larger second pump. These problems exist also when a main electric oil pump substituting for a first mechanical oil pump is used during switching.
The present invention has been conceived in view of the above, and suppresses deterioration of a second pump to thereby prolong the life of the pump and avoid need for a larger second pump.
According to the present invention, there is provided an electric oil pump control device, comprising a driving source; a driving source controller for activating and suspending operation of the driving source under predetermined condition; a first pump; a second pump driven by electrical energy; a pump controller for operating the second pump when the first pump is not operating; and a hydraulic mechanism driven by oil pressure supplied from the first pump and the second pump, wherein the pump controller causes the second pump to operate until a successive operating time of the second pump exceeds a predetermined acceptable operation time, and the driving source controller activates the driving source when the successive operating time of the second pump exceeds the acceptable operation time.
According the present invention, the pump controller controls the second pump so as to operate when the first pump is not operating, so that the hydraulic mechanism is driven by oil pressure supplied from the second pump when the first pump does not operate. Here, the pump controller controls the second pump to operate when the successive operating time of the second pump does not exceed a predetermined acceptable operation time, and the driving source controller activates the driving source when the successive operating time of the second pump exceeds the acceptable operation time. This arrangement limits the successive operating time of the second pump, thereby suppressing wear of the second pump and thus prolonging its life. Moreover, need for providing a larger second pump can be avoided.
According to the present invention, there is provided an electric oil pump control device, comprising a driving source; a driving source controller for activating and suspending operation of the driving source under a predetermined condition; a first pump; a second pump driven by electrical energy; a pump controller for operating the second pump when the first pump is not operating; and a hydraulic mechanism driven by oil pressure supplied from the first pump and the second pump, wherein the pump controller has the second pump to operate until a successive operating time of the second pump exceeds a predetermined acceptable operation time, and the acceptable operation time is set according to a measured value of physical property indicative of a state of the vehicle.
According to the present invention, there is provided an electric oil pump control device, comprising a driving source; a driving source controller for activating and suspending operation of the driving source under predetermined condition; a first pump; a second pump driven by electrical energy; a pump controller for operating the second pump when the first pump is not operating; a hydraulic mechanism driven by oil pressure supplied from the first pump and the second pump; and a prediction device for making running prediction according to a state of the vehicle, wherein the pump controller causes the second pump to operate until a successive operating time of the second pump exceeds a predetermined acceptable operation time, and the acceptable operation time is set according to the running prediction.
In the present invention, the running prediction may be based on a running state of the vehicle and a prediction concerning automatic activation of the driving source or a prediction concerning termination of operation of the vehicle.